In a gas turbine or a turbo freezing machine, an axial-flow compressor, which is one type of axial-flow fluid machinery, is used to compress a gas. Such a type of axial-flow fluid machinery sometimes includes a plurality of variable vanes disposed around a rotor in an annular shape, and a variable vane drive device configured to change directions of the variable vanes.
For example, as disclosed in the following Patent Document 1, the variable vane drive device includes a movable ring disposed at an outer circumferential side of a casing and having an annular shape, a ring support mechanism configured to rotatably support the movable ring, an actuator configured to rotate the movable ring, and a link mechanism configured to connect the movable ring to the variable vane such that the direction of the variable vane is varied by rotation of the movable ring.
The link mechanism includes a rotary shaft fixed to the variable vane to form a cylindrical shape around the axis of the variable vane, a link member having a shaft insertion hole through which an end portion of the rotary shaft passes, and a detent pin configured to restrict the link member to be relatively non-rotatable with respect to the rotary shaft. A pin hole into which the detent pin can be fitted is formed from an end portion of the rotary shaft to the link member into which the end portion is inserted, and recessed in a direction perpendicular to the axis of the rotary shaft. The detent pin and the pin hole form an interference fit.